Improvement in pianos



tleirittt' nes Letters Patent No. 109,172, dated ovember 15, 1870.

IMPRQVEMENT IN PIANOS.

mscmauxsmmazommmmemrmmamgpmonsem To Il whom. it may concern;

Be it known that I, OLE BULL, professional musicia-n of Valestrand, near Bergen, Norway, residing a large part of thel time in the city, county, and State of New York, have invented certain new and useful Improvementsin Pianos; and I do herehydcclaie that the following is asutticiently full and exactdescription thereof, to enable others skilled in the art to successfully put my invention in practice.

1 will proceed to describe the novel features ol' my piano, with so much of the ordinary features as seems necessary to properly indicate their relation thereto.

The accompanying drawing forms a part of this specitication.

Figure 1 is a plan view of thc iron frame with some of the accompanying parts.

Figure 2 is a plan view of the sounding-board and bridges, with a portion of the iron frame-work.

Figure 3 is a vertical section thnough a portion of -the sounding-hoardsl and (mme, including also the casing at the back, and a portion of the le".

Figure 4 is a corresponding section through some of the parts nearer the front.

These last tivo figures arc on a much larger scale than either of the preceding.

Figure 5 is a vertical section through the iron frame .on a smaller scale.

Figure 6 is a transverse section through 'the ease, including also the sounding-boards and tiame.

Figure 7 is a longitudinal section tln'oughthc enthe sounding-board.

Figure 8 is a section through the bridge and the adjacent part of the sounding-board on a larger scale.

Figure 9 is a vertical section through a leg.

Figure 10 is a plan view ot' the leg.

The action, keys, pedals, &c.,' as also the exterior case, may be ot' ordinary, or anysuitable construction.

l will assume that it is a grand piano of the besteon struction.

Istrengthen the iron frame on which the' strings are stretched by deep narrow bars, extending in thc direction ot thcsstrings. These bars are exposed to a strain of compression, and, being below the level of the strings, the tendency ot' the strain of the strings is to curl the frame upward. '.lo prevent this, I ap ply trussrods, of iron or steel, with turn-buckles, to allow the rods to he tightened. These rods press under asms, extending downward from the before-dcserihod narrow bars, and [set them tight before tightening the strings. lhc frame is furthermore strengthcned h v cross-hars.

ily this arrangement of the frame Lavoid any iuterl'ering with tho continuity of tho sounding-hoard hy necessitating any hole or holes therein.

The grain of the wood in the sounding-board is paralle] or nearly parallel to thedirection o'the strings.

I glue, on the under side of the sounding-board, ribs or strengthening strips of wood, which are of little breadth, but of greater depth. The depth sgfeatest ifi the middle, and decreases toward each end. Instead ot' gluing those transversely, or directly across the grain ot' the wood in the sounding-board, I place them very nearly longitudinally or parallel to the grain, but I put thom a little oblique. I esteem this matter one ot' great importance to the success of the in\'ention in giving a loud and perfectly clear tone.

I preter to make this obliquity only a little more than sullcient to cover the entire grain of the board, with the Obliquity ot' the strengthening ribs; that is to say, it a series ol' lines is drawn along' the surface of the somnling-board, corresponding to the grain thereof, the ohliquity ol the. ribs is such that the t'ront end ol' one rib `touches or slightly crosses the line which is touched or slight-ly crossed-hy the back end of the adjoining rib. l have given much attention to this subject, and esteeln this the preferable degree ot' obliquityg but it may be made a little greater or a. little lesser without materially interfering with the purity of the tone.

This construction of the sounding-hoard, with the ribs thus arranged, provides not only for the-perfection oi' the sonorous qualities of the sounding-board when new, but avoids any appreciable deterioration with age. I tind this improves with age.

The best example in which I have embodied my improvementsa grand piano, ot'excellcut workmzur ship and materialshas considerably improvcddurtng the few months which it hashcen tuucd and in use. At cach examination it has heen found to excel its previous condition. vI ascrihelhis result, in part at least., to'the peculiar construction of the sounding-boards.

l have devised peculiar meats for isolating the sounding-board and frame from the external case ot' the instrument. I can bolt or otherwise fasten the parts together directly or through the medium of glass or other material ot good sonorous qualities, in addition to my mode of mounting, if I plea ,e; but; l have succeeded best by entirely disconnecting or isolating the frame from tho aise, by bolting both firmly upon a U-shapcd iron, which is, iu turn, .'iratxly mounted upon thclegs. 1 make two such connections at the rear, and these are the only unions between the fmme and the case, except at the front. The soundingn hoard is supported upon an iron frame at a proper distance below the strings.

The unity of structure of the sounding-board, and the absence not only of any holes or interruptions from such cause, but also of any erossglued or crossmnnceted parts, as also of any screws or analogous Y ot' cach.

foreign parts to interfere with its vibration, gives an t-tlbctuot-hetore produced in this class of instruments.

lprcsu the sounding-board hack tinnlv, so as to maintain a ver)- solid hearing, hy the aid of revenul distributed at, short intervals along the front. of the sounding-hund. I make the bridges hollow. I can secure them to the sounding-hoard either h v gluing or simply sinking them to a slight depth into the material of the sotnnliug-hmtrd. 1 pttfer the latter eonstruct-ion, believing: that any part glued across the grain of the sounding-board is liable to interfere with the etect. The hollow structure ot the bridge gives an increased sonorous chatactcrto the instrument. It sounds louder as well as purer.

At; the front; of thc sonndingdioznd l mount. a .series of posts, inclined forward, a'td a hoard similarly inclined. The principal object of thisis to cause the sound to he retiectcd or reverhelatcd upward, and to prevent; it funn traversing too tinteh forward into the act-ion.

kI attach lunch tnptn'taum: to this feature ol' the invention. I consider that lunch ot' tin.` sound which travels forward into the action and into tho recesses iu the fmut part of tlte instntment is practically lost in its eeet; upon an audience. 'lhe chief ell'vct of this patt et'tuy invention is to int-tease the loudness ot' the sound` l I make the legs ofthe piano hollow'. Ialso pro vide openings tht-.rein which may he closed at pleasure h v suitable valves; All the ordinary and uws-t ap' ).-roved appliauecnmay he used for preventing thtes:- cape ot' sound through the floor, such as glass-casters, or the like.

Myiurention does not prevent tlnemployment ol most; ot' the improvements known in pianos, hut hartnonizes therowitltmnd contributes to the good rtlbct I have alture explz'titml that. tiro rihs ttudcr tn v sounding-hmml should extend nearly parallel with thtgtain of the hoard, but slightly inclined. I limi than hyvaryng the relative depth and thickness of the several tilts, l. can vary the qualities ot the sound withincousidexal-le limits., 'L'he ribs .should always he deeper in the middle and tapering,r toward cat-lx end, as indicated in figs. 3 and Land the sound will, with construction ot' the` soutnling-hoartl, as here replesented, he highLvclvar and puro. .ity placing the ribs more nearly parallel with the. grain of the hoard, and making lhetu narrower and deeper, l can make the tune peculiarly hrilhaut, :nul hy making the ribs` thlckcr and less deep, and placing them a little tuowv oblique than hero rut'nvsented, I can give, in soute measure, a conti-atv etl'ect, and make. the tone lessbrilliant and more mellow.

13)' propt-r attention to these points l van modifi: thcchatacter ot' my pianos to suit the uses l'nr which they are more particularly intended, or the tastes ot' thepnrchasets.

Some patts ot' in v invent-ion may he applied with success in square, upright, and all the several varioties of pianos, and the nnnlitiration.,- necessary to adapt these to each form ill ho obvious.

Referring w the dt-.twiug- A is the soundiug-hoardg 15, the stout. traute `ot` iron or Ystt-fl in which it is supported; and

(l, the external case.

The ribs on the under sidi: ot" the sounding-hoard Aare marked A'.

-The arms extending down from the frame B are marked Il'.

The ordinary sonthar.; which .st-rvu :ri struts lo resista crushing strain, a nuaited Il?, .nid extend across the flame in :x direction nt-:n'ty or exactl) para',- lcl with the suing.

The tension due to the strings being exerted in a plane considerably above the plane of the [mmc and bars or struts B, -there, is a tendency of the entine t'mme B to cnrl upward, that is, to rise at the i'rontand rear and to sink in t-he middle. But I counteniet this strain eteetually by tension-rods, or trussrods, I ),a| 'rtnged as represent/ed. v

The strain on these rods D tends to curl the frame downward at the front and hack, and upward in the middle. I so pmportnn the tension of the strings that the tendencies to curl the trame in opposite directions conntcrlxdan each other.

The inclined posts, under and near thefmnt. of my. sounding-hoard, are represented hy E. The corresponding board is marked G. f I L The screws, which press heavily-,against the fronte thtl sounding hoard, are marked h. 1 f

The hollowhridge, sank slightly in the-sounding ,.1 hoard A, is marked n. Y

I connect. the frame B bythe aid ofarms.B,toone Y arm ofthe U-shaped inon I, and Iconnect the back.. ..2 3 portion of the tiamc G to the other nrm et the same iron. Iholt the lower porton`-or bend of this iron I to the topot the backlog M. j j

All the legs of my piano are made et' thebt and L. most sonorouswrmd, and are made hollow, as indicated hyligAt. 1 They are pmrided with .jt seat, nl, and valve in plat-c.V 1* 'v fw These valves, X, of which there may be mail. Yariousiy arranged to tir upon conespouding seats, are operated hy connections, not. n'presented, hytneans ot"l a pedal convenientlyplaced to he acted on bythe pet-. fermer.

l can malte the bottom of my hollow logs either y eatin-I viosed or pattialtyopcn. I have represented' the construction which Ipre'fer, in which the honouris permanently open, and is provided wit-h erstem' which turn nith great tivedotn. Y *i* I do not confine myself to tho precise form ot'ith several details. l

The hats It, in the flauto-, forni, in connection.v with xln rods .l,`a vspecies ot' lengthening frame, y analogous to the ti1tss-work ot' bridges, and I propose to employ vat-ions modifications of the forms and propottions of these parts, which I desigmtc generally as trnssing. Y Y

.l have thus .far said nothin'ar of two featui'es which t 1 .I wnsiderimportant, though some portion of tho henctit of tn v invention may he obtained without any` other single tentait). In other words, although Ipre ter to use ail my improvements and combinations, l do not limit myself thereto. Y

The features remaining to be described are the cross bars l' in the cast-iron hante, and the second or enhsonndiug-lnvtrd i'..

'lln` cross-hars B* are east in one with the matti naine it, and with 'the longitudinal hats B', and serre to stiti'ei both, and lottieulariy to defend the latter against hucivlitn.f or heading toward one side or the other.

The. second sounding-hoard I' has its ribs, P', correspondiug in form and armogemcnts to the ribs A' on the upper or main sounding-inlaid A'lbutin au inverted position.

The rihs` laru. ou 'the upper face of the lower sounding-hoard, which rests on screws which press it up firmly into a. rebate in the lower edge of the casing C.

I claim as follows:

l. The series ot' parallel ribs A', on the whole louer surface of the sounding-imam, and standing nearly parallel to tho gtnin of the wood 'thereitn as andfor the purposes specitied.

L. iu connection with tlv: ve o truss-rods D, thc tig-id flauw-work l?, atrae. ,1d t el): to each other and to the piano-string.` .a sp ttoi.

3. The U-shaped irons xniitinf.' 2l.' legs, c; e, and

sounding-hoard, and it s conncctions. mul holding the sented, nud reflecting the Sound hnckwanl and upward, sounding-bomd pmctically isolated from thc ense, ns as specified. specified. 7. The `ksoul:ding-board 1 P', amngcd, as nepri.`

4. The sclens h h, pressing against the front edge sented, ucar the lower edge of the msiug C, in oonnl' the sounding-board to graduale :unl insure a lwctiou with the inclined tient-hoard G, as set forth.

` In {estimony whereof, I- have hereunto set my name `snlliciently rm pressure thereon, :unl nrmng4 :is

in tlw nrc-sence of two subscribing witnesses.

. shown, rclntivelyto the inclined front board G, nsxp om: BULL cicd.

5. The valves N, munged as rcpreseutul, to cun- I \\'tnesseea tml apertures in-the hollow legs of a plano. A Tnorus D. STETSUX,

l C.- C.l Lrvrxom 6. The inclined front-benul G, ammged'ns renre- 

